The present invention generally relates to the treatment of hazardous chemical wastes, and more particularly to the degradation of tributyl phosphate in organic chemical waste mixtures using a novel, newly-discovered strain of bacteria. Acinetobacter genospecies 11 (ATCC 55587). A deposit of the microorganism has been made in the American Type Culture Collection, Rockville, Md. on Jun. 10, 1994, and is available under conditions set forth in 37 CFR. Throughout this specification the terms Acinetobacter sp. ATCC 55587, Acinetobacter BGL1a and Acinetobacter genospecies 11 are used alternatively to refer to the same organism.
The effective treatment of hazardous chemical waste materials is of considerable importance for numerous reasons. Primarily, the health, safety, and welfare of the general public is of greatest concern. In accordance with this fact, increasingly strict local and national regulations have been enacted which relate to chemical pollution involving virtually all types of industrial waste. One chemical material of recent concern involves a material known as tributyl phosphate (hereinafter "TBP") which has the following chemical structure: ##STR1##
TBP is primarily used throughout the world as an extractant for the processing and recycling of nuclear fuel materials as described in Science and Technology of Tributyl Phosphate, Vol. III, CRC Press, Boca Raton, Fla., edited by Schulz, W. W., et al. (article therein entitled "Purex Process Flowsheets", pp. 55-79 (1990) by Swanson, J. L.). Typically, odorless kerosenes, alkane mixtures, and/or chlorinated alkanes are combined with TBP as diluents when TBP is used as a nuclear fuel processing agent. TBP also has other uses, including but not limited to use as a plasticizer, hydraulic fluid, herbicide, insecticide, an extractant for rare earth metals, a catalyst, a corrosion inhibitor, and as an antimicrobial/thermal decomposition resistivity additive in petroleum-based hydraulic fluids and cutting oils (see Science and Technology of Tributyl Phosphate, Vol. II, CRC Press, Boca Raton, Fla., edited by Schulz, W. W., et al. (article therein entitled "Miscellaneous Industrial Uses", pp. 81-141 (1987) by Jones, C. J., et al.). TBP has even been used to deactivate the human immunodeficiency virus (HIV) during blood fractionation as noted in Current Studies in Hematology and Blood Transfusion, Vol. 56, S. Karger, Basel, Switzerland (article therein entitled "Investigations into the Application of Tri(n-butyl) Phosphate/Detergent Mixtures to Blood Transfusions", pp. 83-96 (1989) by Horowitz, B.). Accordingly, there are many important uses for TBP in a wide variety of technical fields. However, TBP waste materials are primarily generated in the nuclear fuels processing industry in the form of oily mixed liquid wastes containing a wide variety of organic materials including but not limited to dodecane, tridecane, tetradecane, pentadecane, kerosene, turbine oil, chlorinated alkanes, and others. These mixed waste materials may also include radioactive waste compounds therein. For example, it was estimated that about 6 million gallons per year of aqueous TBP and radioactive mixed waste materials were being generated from nuclear fuel processing operations at Hanford, Wash. (U.S.A.) which is a primary U.S. Government nuclear fuel processing facility. As a result, significant problems exist regarding the disposal of these materials in a safe and effective manner.
The importance of effectively treating/handling TBP and TBP-containing mixed wastes is characterized by numerous adverse side-effects experienced by humans coming in contact with these materials. For example, TBP is considered a hazardous material in that it is harmful if inhaled, ingested, or absorbed through the skin. TBP vapor is highly irritating to the eyes, nasal mucosa, and upper respiratory tract. It specifically causes skin irritation and nausea. While the long-term effects of TBP exposure are not entirely understood at present, it is assumed that TBP exposure can generally cause damage to the human central nervous system. In addition, it should be noted that the organic materials (e.g. long-chain chlorinated and non-chlorinated alkanes) usually combined with TBP in the above-described mixed liquid waste materials may also be considered environmentally hazardous.
Typically, organic mixed liquid wastes containing TBP are stored in metal tanks and drums which are either above-ground or buried underground. In either case, if the integrity of these tanks or drums is compromised through deformation, corrosion, or the like, considerable environmental problems can result. For example, the escape of mixed organic liquid wastes containing TBP from above-ground tanks and drums can cause a variety of adverse effects with respect to human and animal life as described above. Regarding underground tanks and drums, the leakage of TBP-containing waste materials can cause ground water/soil contamination as the waste materials percolate, migrate, and diffuse through the soil.
In an attempt to solve these problems, conventional waste treatment methods have been used in connection with TBP-containing mixed organic wastes. These traditional methods include: (1) incineration; (2) adsorption onto solid media (e.g. activated carbon); and (3) concentration by evaporation and further storage of the concentrated product. However, all of these methods either generate further polluting wastes or do not physically eliminate the organic chemical agents of concern. Also, they typically involve considerable expense and frequently encounter objections by the general public (e.g. with respect to incineration and the by-the general public (e.g. with respect to incineration and the by-products generated therefrom).
Accordingly, prior to development of the present invention, a long-felt need existed for an effective and permanent process designed to eliminate TBP (and other organic wastes combined therewith) from liquid waste mixtures. The present invention satisfies this need in a highly effective and efficient manner as described below.